Upon several map developers request I've uploaded this extensive building footprint polygon layer developed by the USDA. The layer is suprisingly comprehensive and could be a welcomed addition to any future map updates. You'll have to clip out your are of interest. It's a nice visual reference for any new mapset. See my Yogamaps-Montana Topo and Public Land for a few screenshots of how the building footprints can look in a map. Link: http://www.gpsfiledepot.com/maps/view/87

The building type or association is in the 'FCSUBTYPE' attribute and the codes are as follows: